   5 REM BLACK HOLE BY BILL ECKEL
  10 DIM X(9)
  14 FOR I=1 TO 9
  16 LET X(I)=0
  18 NEXT I
  20 LET X(5)=1
  25 CLS 
  30 PRINT ," BLACK HOLE"
  32 PRINT 
  34 PRINT 
  35 LET I=1
  40 PRINT ,;
  42 FOR A=1 TO 3
  44 IF X(I)=1 THEN PRINT "*";
  46 IF X(I)=0 THEN PRINT "O";
  48 LET I=I+1
  49 PRINT " ";
  50 NEXT A
  52 PRINT ,;I-3;" ";I-2;" ";I-1
  53 PRINT 
  54 IF NOT I=10 THEN GO TO 40
  56 PRINT 
  58 PRINT 
  60 GO SUB 1000
  65 PRINT "WHICH STAR?"
  70 INPUT S
  75 IF S<1 OR S>9 THEN GO TO 70
  78 IF X(S)=0 THEN GO TO 70
  85 LET X(S)=0
  90 GO SUB S*100
  95 GO TO 25
 100 LET B=2
 110 GO SUB 980
 120 LET B=4
 130 GO SUB 980
 140 LET B=5
 150 GO SUB 980
 160 RETURN 
 200 LET B=1
 210 GO SUB 980
 220 LET B=3
 230 GO SUB 980
 240 RETURN 
 300 LET B=2
 310 GO SUB 980
 320 LET B=5
 330 GO SUB 980
 340 LET B=6
 350 GO SUB 980
 360 RETURN 
 400 LET B=1
 410 GO SUB 980
 420 LET B=7
 430 GO SUB 980
 440 RETURN 
 500 LET B=2
 510 GO SUB 980
 520 LET B=4
 530 GO SUB 980
 540 LET B=6
 550 GO SUB 980
 560 LET B=8
 570 GO SUB 980
 580 RETURN 
 600 LET B=3
 610 GO SUB 980
 620 LET B=9
 630 GO SUB 980
 640 RETURN 
 700 LET B=4
 710 GO SUB 980
 720 LET B=5
 730 GO SUB 980
 740 LET B=8
 750 GO SUB 980
 760 RETURN 
 800 LET B=7
 810 GO SUB 980
 820 LET B=9
 830 GO SUB 980
 840 RETURN 
 900 LET B=5
 910 GO SUB 980
 920 LET B=6
 930 GO SUB 980
 940 LET B=8
 950 GO SUB 980
 960 RETURN 
 980 IF X(B)=0 THEN GO TO 986
 983 IF X(B)=1 THEN LET X(B)=0
 984 RETURN 
 986 LET X(B)=1
 990 RETURN 
1000 FOR I=1 TO 9
1010 IF X(I)=1 THEN GO TO 1050
1020 NEXT I
1025 PRINT "YOU BLEW IT"
1030 PRINT "YOU ARE LOST IN SPACE FOREVER"
1040 STOP
1050 IF X(5)=1 THEN RETURN 
1060 FOR I=1 TO 4
1070 IF X(I)=0 THEN RETURN 
1080 NEXT I
1090 FOR I=6 TO 9
1100 IF X(I)=0 THEN RETURN 
1110 NEXT I
1120 PRINT "CONGRATULATIONS"
1130 PRINT "YOU FOUND THE BLACK HOLE"
